1. Field of the Invention
This invention relates to a wire guide apparatus which can be effectively utilized for a wire driven mechanism such as a robot arm for performing various operations.
2. Description of Prior Art
The inventor previously pursued research for realizing a robot arm simulating a human arm in both function and appearance with a small-size, light-weight simple mechanism and proposed an anthropomorphic robot arm (U.S. patent application Ser. No. 440,113, now U.S. Pat. No. 4,986,723).
In the proposed robot arm, a drive source is provided on the stem side of the arm in order to make the movement of the arm as a whole smooth and is coupled via wires to a hand section for power transmission to and operation of hand section. However, for enabling operations of the hand section to be performed accurately it is necessary to hold the length of the wires passing through an elbow portion constant at all times irrespective of the extent of bending or streching of the arm. The length of wires passing through the elbow portion of the arm can be held constant if the wires are bent sharply at the elbow portion without use of any pulley or the like. Where a pulley or the like is used, however, the length of the wire is changed in accordance with the contact length of the pulley. Therefore, if the arm is bent greatly at the elbow portion, a large length of wire is required, while reduction of the degree of bending causes looseness of the wires. Therefore, it is difficult to transmit accurate motion to the hand section.
An object of the invention is to provide a wire guide apparatus which permits the length of wires passing through a joint section (an elbow portion) of a wire driven mechanism to be substantially constant irrespective of the extent of bending of the wire driven mechanism.